1. Field of the Invention
The present invention relates to a method of making a nozzle chip.
2. Description of the Related Art
A nozzle chip is used in a liquid ejection head that ejects a liquid from ejection orifices. Examples of a liquid ejection head include an ink jet recording head that performs recording by ejecting an ink toward a recording medium such as a sheet of paper. Japanese Patent Laid-Open No. 2009-166492 describes a method of making a nozzle chip of an ink jet recording head.
The method of making a nozzle chip described in Japanese Patent Laid-Open No. 2009-166492 will be briefly described. First, an element substrate, which includes energy generating elements that generate energy for ejecting a liquid from ejection orifices, is prepared. Next, a positive photosensitive resin layer including an optical absorption agent is formed on the element substrate. Then, the positive photosensitive resin layer is exposed to light by photolithography, and thereby a pattern having the shapes of flow paths is formed. Next, a negative photosensitive resin layer, which will serve as an ejection orifice forming member, is formed so as to cover the pattern, the negative photosensitive resin layer is exposed to i-line light (wavelength 365 nm) through an exposure mask having a predetermined light transmitting pattern, and an ejection orifice row is formed by performing a developing operation. Lastly, by removing the pattern through the ejection orifices, flow paths having predetermined shapes are formed in the ejection orifice forming member.